#include<netinet/in.h>  
#include<sys/socket.h>  
#include<unistd.h>  
  
#include<stdio.h>  
#include<string.h>  
  
#include<event.h>  
#include<event2/listener.h>  
#include<event2/bufferevent.h>  
#include<event2/thread.h>  
  
  
void listener_cb(evconnlistener *listener, evutil_socket_t fd,  
                 struct sockaddr *sock, int socklen, void *arg);  
  
void socket_read_cb(bufferevent *bev, void *arg);  
void socket_event_cb(bufferevent *bev, short events, void *arg);  
  
int main()  
{  
    //evthread_use_pthreads();//enable threads  
  
    struct sockaddr_in sin;  
    memset(&sin, 0, sizeof(struct sockaddr_in));  
    sin.sin_family = AF_INET;  
    sin.sin_port = htons(9999);  
  
    event_base *base = event_base_new();  
    //使用evconnlistener_new_bind函数 代替原来的事件申请函数（event_new）
    evconnlistener *listener  
            = evconnlistener_new_bind(base, listener_cb, base,  
                                      LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE,  
                                      10, (struct sockaddr*)&sin,  
                                      sizeof(struct sockaddr_in));  
    event_base_dispatch(base);  
  
    evconnlistener_free(listener);  
    event_base_free(base);  
  
    return 0;  
}  
  
  
//一个新客户端连接上服务器了  
//当此函数被调用时，libevent已经帮我们accept了这个客户端。该客户端的
//文件描述符为fd
void listener_cb(evconnlistener *listener, evutil_socket_t fd,  
                 struct sockaddr *sock, int socklen, void *arg)  
{  
    printf("accept a client %d\n", fd);  
  
    event_base *base = (event_base*)arg;  
  
    //为这个客户端分配一个bufferevent  
    bufferevent *bev =  bufferevent_socket_new(base, fd,  
                                               BEV_OPT_CLOSE_ON_FREE);  
  
    bufferevent_setcb(bev, socket_read_cb, NULL, socket_event_cb, NULL);  
    bufferevent_enable(bev, EV_READ | EV_PERSIST);  
}  
  
  
void socket_read_cb(bufferevent *bev, void *arg)  
{  
    char msg[4096];  
  
    size_t len = bufferevent_read(bev, msg, sizeof(msg)-1 );  
  
    msg[len] = '\0';  
    printf("server read the data %s\n", msg);  
  
    char reply[] = "I has read your data";  
    bufferevent_write(bev, reply, strlen(reply) );  
}  
  
  
void socket_event_cb(bufferevent *bev, short events, void *arg)  
{  
    if (events & BEV_EVENT_EOF)  
        printf("connection closed\n");  
    else if (events & BEV_EVENT_ERROR)  
        printf("some other error\n");  
  
    //这将自动close套接字和free读写缓冲区
    bufferevent_free(bev);  
}  

